Cell type solvent extractor



June 3, 1969 W. DEPMER CELL TYPE SOLVENT EXTRACTOR Filed Jan. 4, 1967 In ven tor W/LHELM DEPHE R Maia! 1/ w his ATTORNEY United States Patent 3,447,909 CELL TYPE SOLVENT EXTRACTOR Wilhelm Depmer, Kielmannseggstr. 86, 2 Hamburg- Wandsbek-Marienthal, Germany Filed Jan. 4, 1967, Ser. No. 607,187 Claims priority, applicationoGermany, Jan. 4, 1966,

Int. Cl. B01d i1/02, 11/00 US. Cl. 23-269 Claims ABSTRACT OF THE DISCLOSURE Background of the invention The present invention relates to continuous solvent extractors of the cellor carrousel type. More particularly, the invention relates to improvements in the construction of grates in cell type solvent extractors. Such extractors are used for the continuous extraction of oils and soluble substances from solid materials with the help of solvents.

My Patent No. 3,131,202 discloses a multi-stage solvent extractor wherein two or more superimposed tiers of sector-shaped bottomless cells orbit about a common vertical axis above horizontal grates having openings for evacuation of the solid fraction of a mixture Containing solid and liquid fractions which is fed into successive cells immediately downstream of the respective opening. The liquid fraction escapes through the perforations of the respective grates and is recirculated or removed. Such liquid fraction consists of solvent and partially or fully concentrated miscella.

It is an important object of my present invention to improve the construction of grates in cell type solvent extractors in such a way that the openings of the grates permit substantially unimpeded escape of liquid fraction but effectively retain the solid fraction of the mixture which is contained in the cells.

Another object of the invention is to provide a selfcleaning grate for use in continuous carrousel or cell type solvent extractors.

A further object of the invention is to provide a grate which can be readily installed in presently known cell type solvent extractors.

An additional object of the invention is to provide a grate which can be used with equal advantage in larger and smaller solvent extractors, which is of simple construction, and which can be cleaned or swept automatically when the solvent extractor is in use.

A concomitant object of the invention is to provide the solvent extractor with simple but effective means for continuously cleaning the grate or grates in the course of the extracting operation.

Still another object of the invention is to provide a grate which need not be discarded if a certain portion thereof breaks down or wears away.

Summary of the invention The invention resides in the provision of an improved solvent extractor wherein at least one bottomless cell orbits about a substantially vertical axis to advance a mixture of solid and liquid fractions along the upper side 3,447,909 Patented June 3, 1969 ice of a preferably horizontal grate which is provided with a preferably sector-shaped opening for evacuation of the solid fraction from the cell. The improvement consists in that the grate comprises a plurality of arcuate grate bars defining between themselves a plurality of arcuate slots or passages for evacuation of the liquid fraction. The centers of curvature of the grate bars and of the slots are located on or at least close to the vertical axis.

The width of the slots is such that the grate bars retain the solid fraction which is evacuated through the opening when the material in the cell completes a little less than one full revolution. The width of the slots preferably increases in downward direction to prevent clogging with particles of the solid fraction. The grate may consist of a single piece of suitable metallic material, or it may be assembled of several sectors whose area preferably (but not necessarily) equals the area of the opening.

In accordance with another feature of my invention, the extractor may be provided with cleaning means for the upper side and for the slots of the grate. Such cleaning means may be constituted by one or more brushes secured to one or more cells to sweep the upper side of the grate when the cells rotate.

The novel features which are considered as characteristic of the invention are set forth in particular in the appended claims. The improved solvent extractor itself, however, both as to its construction and its mode of operation, together with additional features and advantages thereof, will be best understood upon perusal of the following detained description of certain specific embodiments with reference to the accompanying drawing.

Brief description of the drawing FIG. 1 is a diagrammatic top plan view of a grate which embodies my invention; and

FIG. 2 is an enlarged fragmentary vertical section through the solvent extractor, substantially as seen in the direction of arrows from the line IIII of FIG. 1.

Description of the preferred embodiments Referring to the drawing in detail, FIG. 1 shows a substantially circular grate G having a central aperture for the vertical drive shaft of a cell type solvent extractor. The grate G is disposed in a horizontal plane and is installed in a cylindrical or tubular housing 7 a portion of which is illustrated in FIG. 2. The housing 7 further accommodates a tier of sector-shaped bottomless cells 6 which may be identical with the cells disclosed and shown in my aforementioned Patent No. 3,131,202. The housing 7 may accommodate two or more tiers of cells 6 and then comprises an equal number of horizontal grates G.

The grate G has a sector-shaped opening 4 for evacuation of solid fraction of the mixture which is fed into successive cells 6 at a loading station LS located immediately downstream of the opening 4, it being assumed that the cells 6 orbit about the vertical axis of the housing 7 and travel in a clockwise direction as viewed in FIG. 1, see the arrow 8. Such mixture travels along the upper side of the grate G and into the liquid fraction (including solvent and partially or fully concentrated miscella) is evacuated through the slots 2. The solid fraction completes a little less than one full revolution and is evacuated through the opening 4.

In accordance with an important feature of my present invention, the slots or passages 2 are of arcuate shape and their centers of curvature are located on or close to the vertical axis of the housing 7. Such slots are defined by preferably circular grate bars 1 which are best shown in FIG. 2 and whose cross sections preferably resemble triangles which taper downwardly, i.e., away from the upper side of the grate G. In this way, any particles of the solid fraction which happen to enter the slots 2 are pushed downwardly by the orbiting masses in successive cells and are expelled from the slots to avoid premature clogging of the grate. The slots 2 taper upwardly, i.e., to ward the open undersides of the cells 6. Such undersides are slightly spaced from the upper side of the grate G to prevent excessive friction and comminution of the solid fraction. Furthermore, such mounting of the grate G and cells 6 renders it possible to install in the housing 7 one or more cleaning devices which sweep the upper side of the grate when the extractor is in actual use. In accordance with a presently preferred embodiment of my invention, the cleaning device comprises one or more "brushes 5 which are affixed to the walls of the cells 6 and orbit therewith about the vertical axis of the housing 7. The bristles of the brushes 5 promote the evacuation of solid particles which have penetrated into the slots 2, and such brushes sweep the solid material toward and into the opening 4. Each tier of cells 6 may carry one or more brushes.

The entire grate G may be constructed as a one-piece body which resembles an annulus composed of concentric grate bars 1 alternating with concentric slots 2. Such onepiece grates are very satisfactory in relatively small extractors. If the diameter of the housing 7 is very large, each grate preferably consists of a series of sector-shaped portions 9 whose radially extending walls 3 abut each other in a manner as shown in FIG. 1. The area of each portion 9 may but need not be identical with the area of the opening 4. The area of such opening 4 preferably equals or approximates the area of a cell 6 so that the open underside of each successive cell can be placed into full registry with the opening 4 during each revolution of the tier about the axis of the housing 7. Subdivision of the grate G into sector-shaped portions renders it possible to replace a damaged of destroyed portion 9 independently of the other portions. Such portions 9 may be assembled without the utilization of connectors or, if de sired, their radial walls 3 may be bolted, screwed or otherwise secured to each other.

The minimal width of the slots 2 will depend on the nature of the solid fraction. For example the width of the slots 2 may be in the range of 0.52 mm. It was found that the slots of my improved grate insure substantially unimpeded passage of the liquid fraction but are very effective in retaining the solid fraction. Furthermore, the upper side of the grate G may be provided with a smooth finish to reduce the likelihood of comminution of solid particles. Arcuate grate bars 1 offer very little resistance to movement of solid particles about the axis of the housing 7. The extractor which embodies my improved grate may be utilized for extraction of oils and other soluble substances from mixtures whose solid fraction consists of pulverulent, fibrous or foliate particles or a mixture of such particles. As stated before, the width of the slots 2 will depend on the nature of solid particles, particularly on their dimensions.

Since the undersides of the cells 6 are open, the contents of such cells are compelled to travel along the upper side of the grate G and bring about an automatic cleaning action which is further enhanced by the provision of one or more brushes 5. The better the cleaning and selfcleaning action, the greater is the efliciency of the extractor. The self-cleaning feature is due to the fact that the width of the slots 2 increases downwardly.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features which fairly constitute essential characteristics of the generic and specific aspects of my contribution to the art and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the claims.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims:

1. In a solvent extractor wherein at least one bottomless cell orbits about a substantially vertical axis to advance a mixture of solid and liquid fractions in an orbital path along and in contact with the upper side of a grate which is provided with an opening for evacuation of solid fraction from the cell, the improvement which consists in that the grate comprises a plurality of continuous circular grate bars defining between themselves a plurality of arcuate slots extending in the direction of said orbital path up to said opening for evacuation of solid fractions from the cell and serving for evacuation of the liquid fraction, the centers of curvature of said continuous circular grate bars being located at least close to said axis so that such grate bars will offer at most minimal resistance to movement of the solid fraction about said axis in said orbital path.

2. The improvement as defined in claim 1, wherein said slots together form a series of concentric passages about said axis.

3. The improvement as defined in claim 1, wherein the width of said slots increases downwardly from the upper side of said grate.

4. The improvement as defined in claim 1, wherein said grate comprises a plurality of sectors.

5. The improvement as defined in claim 4, wherein said grate is of circular outline.

6. The improvement as defined in claim 1, wherein the cell is slightly spaced from the upper side of the grate; and further comprising cleaning means arranged to travel along the upper side of the grate.

7. The improvement as defined in claim 6, wherein said cleaning means comprises a brush affixed to said cell and arranged to sweep the upper side of the grate.

8. The improvement as defined in claim 1, wherein said grate resembles an annulus whose center is located on said vertical axis, and wherein said opening resembles a sector.

9. The improvement as defined in claim 1, wherein said grate bars are of substantially triangular cross-sectional outline and taper downwardly from the upper side of the grate.

10. The improvement as defined in claim 1, wherein said grate is located in a horizontal plane and comprises a plurality of sectors each having an area corresponding to that of said opening.

References Cited UNITED STATES PATENTS 323,680 8/1885 Holden 210-498 1,483,667 2/ 1924 Landreth 15-21 2,217,324 10/1940 Ohme 134-80 2,588,533 3/1952 Johnson 210-498 X 2,643,659 6/1953 Auten 134-80 2,996,741 8/1961 Fox 15-3.17 X 3,131,202 4/1964 Depmer 23-269 X FOREIGN PATENTS 355,769 9/ 1961 Switzerland. 969,768 9/1964 Great Britain.

NORMAN YUDKOFF, Primary Examiner.

S. J. EMERY, Assistant Examiner.

US. Cl. X.R. 

